The researcher has been cataloguing unexplained sightings and close encounters with visitors from outer space for more than a decade and says the Japanese government is “absolutely aware” of the group’s work and its findings.

“One of the people I have interviewed is Mamoru Sato, who was a wing commander in the Air Self-Defence Force, and who collected testimony from a number of military pilots who had interacted with UFOs,” he said. “Those reports were met with ridicule and the authorities refused to take him seriously.”

Among the incidents that Sato documented was a sighting of a “flying saucer” at close range before the craft disappeared at a rapid speed, and an entire squadron of pilots on the ground at an airbase witnessing a series of highly reflective craft that were also moving at a speed beyond the capabilities of a conventional aircraft.

In another case, a squadron was scrambled to intercept an unidentified object but it quickly vanished.

Japan appears to be something of a hotbed for UFO sightings, with a “flashing green orb” reported in the skies above Niigata in November 2016, and “10 white globes” floating above Osaka in July 2015 and “mystery lights” witnessed by dozens of people over Okinawa in January 2014.

In September 2009, Miyuki Hatoyama, the wife of then-Prime Minister Yukio Hatoyama, attracted headlines over a book in which she claimed to have had an extraterrestrial experience 20 years before.

“While my body was asleep, I think my soul rode on a triangular-shaped UFO and went to Venus. It was a very beautiful place and it was really green,” she wrote. Her husband reportedly told her that it was probably just a dream.

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Sullivan said the Japanese public was interested in knowing more about UFOs, but “a filter has been applied to the information by the authorities that has effectively seen the issue relegated to cult status”.

“People are hungry for information to be released, and in all the years that I have been travelling across Japan, I’ve heard a lot of people’s UFO experiences,” he said.

JCETI hosts two or three events each month, with people claiming to have had an encounter with an alien craft attending virtually every meeting and sharing their stories and photos.

“We've also got some amazing footage from our regular sky-watch events, with places such as Hokkaido, Okinawa and Tohoku – places that are far away from the big cities – proving to be the best hotspots,” Sullivan said.